Age-dependent semiology of frontal lobe seizures.

Introduction: Frontal lobe epilepsy is the second most frequent origin of focal epilepsy. Various studies have discussed localizing aspects of ictal signs in frontal lobe epilepsy; the effect of age on semiological manifestations has, however, not been analyzed so far.

Material And Methods: We retrospectively analyzed video-documented semiological signs in a cohort of 122 consecutive patients aged 0-70 years (mean age: 24.9 years) with EEG/MR evidence for frontal lobe epilepsy undergoing video-EEG telemetry assessment between 1999 und 2016.

Results: In this patient cohort, most common etiologies were focal cortical dysplasia (48%) and tumors (16%). Most frequent ictal manifestations overall were impaired language comprehension (60.3%), unilateral tonic posturing (58.9%), unilateral cloni (46.6%), versive movements (44.5%), vocalization (42.5%) and impaired reactivity to non-verbal stimuli (40.4%). With increasing age, sign of four (p = 0.019), dystonic posturing (p = 0.026), changes in heart rate (p = 0.014) and impaired reactivity to non-verbal stimuli (p = 0.009) occurred significantly more frequently. In contrast, myoclonic components were significantly less frequent observed in the higher age group (p = 0.037).

Conclusions: Frontal lobe seizures can be categorized into different behavioral manifestations related to involved symptomatic brain regions, including clonic, bilateral asymmetric tonic seizures and complex motor phenomena. In this cross-sectional study, we found age-related changes in the frequency of both, motor and non-motor semiological elements. Especially simple lateralized motor signs like dystonic posturing, sign of four and version were more common with increasing age. Age-dependent alterations in phenomenology may reflect maturation in connectivity and seizure propagation within and beyond the frontal lobe, and affect the localizing and lateralizing value of ictal phenomena.